CIA, FBI flagged Boston suspect

US: Both the CIA and the FBI flagged the deceased Boston bombing suspect over possible terror ties, but he slipped through the fingers of investigators, officials said Wednesday.

The revelations raised fresh questions over why US authorities did not further investigate Tamerlan Tsarnaev, who was killed during a shootout with police last week, and in doing so possibly prevent the attacks.

The CIA asked the top US counterterrorism agency to add Tsarnaev to a terror watchlist more than a year before the bombings, a US intelligence official said.

The spy agency made the move after Russian officials contacted their CIA counterparts in September 2011 about their concerns over Tsarnaev.

His younger brother Dzhokhar, 19, has been charged with federal terror offenses including the use of a weapon of mass destruction in the twin blasts on April 15 that killed three and wounded 264 people at the Boston Marathon's finish line.

AFP